Dual location NAS?

I am looking for a NAS-solution.
I like models with HDMI and remote control for media player
For redundancy I want one NAS in each of my homes, and set up mirroring between the two.
Only mirror folder containing private photos and other important documents.
Manually/automatically share capacity for less important, like movies and music.
service to play music, on network attached audio devices supporting DLNA

Maybe: 2×QNAP TS-251+ (or TS-451+), maybe 4 bay for future expansion.

Most importantly I want to store photos and documents with redundant location. I have seen many videos about different RAID, for performance and/or redundancy. RAID 1 is good against general disk failure, but not as good if failure is caused by fire.

Qnap 51+ series are fairly old. Maybe better to consider 53Be if still available. These models would have better 4K support via HDMI. The latest models are 53D with newer LAN ports which is a good thing to have while we are moving towards WiFi6.But you can also stream via DLNA or any network-based streaming app. Then HDMI is not that important.The idea about two NAS systems in remote locations is great. You can set up automated sync tasks and keep your data duplicated effortlessly. This is a much better approach then RAID. But that is needed as well.I hope this helps.